In conventional elevator systems the giving of calls occurs with up/down pushbuttons in the elevator lobbies, by means of which pushbuttons a passenger orders an elevator to his/her departure floor and, after the elevator has reached the departure floor, indicates in the elevator car his/her desired destination floor. Alongside the call-giving method in question also so-called destination call systems are used, in which each passenger indicates his/her destination floor already in the elevator lobby before going into the elevator car. The giving of destination calls takes place by means of a special destination call terminal, either with pushbuttons or by means of a personal identifier, e.g. an RFID (radio frequency identifier) tag. Based on the destination call data, the group control of the elevator group allocates an elevator car for the use of the passenger, which is notified to the passenger e.g. on a display in the destination call terminal. In the same connection the passenger can be given guidance information about where the elevator in question is located with respect to the destination call terminal.
The destination call terminals are typically located e.g. in the elevator lobby as fixed installations. A problem with call terminals that are fixed installations is, inter alia, that they adapt poorly to changes occurring in a building, e.g. if the intended use of the building changes or if large numbers of people sporadically visit the building. Call terminals could also have been installed originally in unsuitable locations from the viewpoint of the smooth flow of traffic, in which case the elevator lobbies can become needlessly congested. The addition of fixed call terminals or the retroactive changing of their location is an awkward and expensive procedure because, inter alia, the cabling connecting to the call terminals must generally be disposed inside the floor structures and/or wall structures of the building. One known solution for solving the problems described above is presented in patent application EP1943175, wherein portable destination call terminals are disposed e.g. in elevator lobbies that are congesting. According to the solution, the destination call terminal is provided with a battery or with some other suitable power source and it is able to communicate wirelessly with the group control of an elevator group. The solution does not in any way, however, present the taking into account of the location or distance of the destination call terminals in relation to the elevators of the elevator group. Since the location of portable call terminals is by nature temporary and dynamic, the elevator group should have information about the location of call terminals, or at least the control parameters that have a value dependent on the location of the call terminals should be updated so that the operation of the elevator group could be optimized to correspond to the actual locations of the call terminals. Also the giving of guidance information for guiding a passenger from a call terminal to the elevator serving him/her is fairly impossible if the elevator group does not have information about the location of the call terminal in the building.